In the following essay by D.A. Carson in his The Limits of Functional Equivalence in Bible Translation he refers to the TNIV. The 2011 NIV had not yet been published. But the points he makes are still relevant.
"The charge is made that the TNIV obscures the quotation from Ps. 8:4, mistranslates three words by turning them into plurals, and loses the messianic plication of 'son of man' to Jesus Christ. I have probably said enough about the use of the plural. Whether the TNIV obscures the connection with Ps. 8:4, will depend a bit on how it translates which has not been published. The serious charge, in my view, is that this loses the messianic application to Jesus Christ. Yet here, too, the charge is less than fair. The expression 'son of man' in the Old Testament can have powerful messianic overtones, of course (see Daniel 7:13,14), but it is far from being invariable: about eighty times it is used as a form of address to the prophet Ezekiel, without any messianic overtone whatsoever. So whether the expression has messianic content or not must be argued, not merely asserted. In Psalm 8, the overwhelming majority of commentators see the expression as a gentilic, parallel to the Hebrew for 'man' in the preceding line. 9Incidentally, gentilic nouns in Hebrew are often singular in form but plural in referent --which may also address the indignation over the shift to the plural.) In the context of the application of Psalm 8:4 to Jesus in Hebrews 2, one should at least recognize that the nature of the application to Jesus is disputed. Scanning my commentaries on Hebrews (I have about forty of them), over three-quarters of them do not think that 'son of man' here functions as a messianic title but simply as a gentilic, as in Psalm 8. If this exegesis is correct (and I shall argue elsewhere and at length that it is), Jesus is said to be 'son of man,' not in function the messianic force of that title in Daniel 7:13-14, but in function of his becoming a human being --which all sides recognize is one of the major themes of Hebrews 2. If one wishes to take the opposite tack --that 'son of man' here is a messianic title --there are competent interpreters who have taken that line. But it is not a matter of theological orthodoxy, since understanding the text one way does not mean that the translator (or the commentator) is denying the complementary truth but is merely asserting that the complementary truth is not in view here."